The embodiments described herein relate generally to a refractory wall and, more particularly, a vessel including a refractory wall, wherein a quantity is being measured.
At least some known vessels, such as gasifiers, produce syngas, fly ash particulates, and slag. As the slag cools within the vessel, some suspended slag and/or particulates may deposit on a refractory wall of the vessel. For example, in an entrained flow gasifier, thick slag flows down the refractory wall of the gasifier. At least some known gasifiers include sensors coupled therein for measuring physical properties within the gasifier. Often, the sensors are coupled within openings defined in and extending through the refractory wall. However, openings in the wall that receive instruments, such as thermocouples, may become covered with a slag curtain such that the slag affects the gasifier instrument measurement and/or control. As such, in at least some known gasifiers, gasifier properties are inferred from those measurements taken behind a flowing curtain of slag and/or taken within the depths of the refractory wall.
At least one known gasifier uses slag drip points to protect instruments and/or metallurgical components. Such drip points are positioned to disrupt the slag flow at an opening in which an instrument is inserted to flow about the opening. However, eventually at the drip points, the slag may form a curtain between a tip of an instrument and the gases to be measured. As such, at least one other known gasifier includes a slag shield that extends through a gasifier wall and into a gasifier process stream. However, known slag shields are coupled to the gasifier wall via mechanical means, such as fasteners, flanges, and welding. Over time, such mechanical means can still be weakened, corroded, fatigued, and/or otherwise damaged by the materials produced within the gasifier.
As such, it is desirable to provide protection for an instrument positioned within a vessel refractory wall such that the instrument can directly measure physical properties within the vessel without interference from fouling, slag, and/or any other flowing layer. Moreover, it is desirable to provide protection for an instrument within a vessel such that the protection does not sustain substantially wear from materials produced within the vessel.